1. Field of the Invention
The present invention comprises a method for reducing the attraction forces between wafers. The attraction forces are caused by fluid cohesion, material adhesion, surface tensions, viscous shear, etc. This attraction forces are reduced when the distance between adjacent wafers is increased.
2. Description of the Background Art
Silicon wafers are generally produced by cutting thin slices (wafers) out of a larger silicon block by means of thin wires and a slurry containing abrasive particles. After the wafers have been sawed they are still glued (with adhesive bonding) to the carrying structure on one side. When this adhesive is released, the spacing between the wafers tends to collapse, and the surface forces between adjacent wafers make it difficult to pull the wafers apart without breaking them. The process of taking the wafers apart from each other is often referred to as singulation or separation.
In order to reduce the manufacturing costs of crystalline silicon wafers, the photovoltaic industry is continuously trying to reduce the wafer thickness. As a consequence of this, the surfaces of the wafers are also becoming flatter and flatter. Hence, the surface forces are expected to increase in the future, while the mechanical resistance of the wafers is reduced due to reduced thickness.